The present invention relates to a data transfer control system, an electronic instrument, a program, and a data transfer control method.
An interface standard called IEEE1394 is widely used in a personal computer (hereinafter may be called “PC”). A protocol called Serial Bus Protocol-2 (SBP-2) is known as a higher layer protocol including a part of a function of a transaction layer of IEEE1394. In SBP-2 (SBP in a broad sense), a command set similar to that of SCSI (MMC-2) is used.
An interface standard called ATA (IDE)/ATAPI has been widely used for storage devices such as a CD drive, DVD drive, and hard disk drive.
Therefore, a data transfer control system having a bus bridge function between IEEE1394 and ATA/ATAPI is necessary for connecting a storage device having an ATA/ATAPI interface with a PC having an IEEE1394 interface.
This type of data transfer control system issues a SCSI (MMC-2) command transferred by using IEEE1394 SBP-2 to a storage device as an ATA/ATAPI command. The data transfer control system decodes the SCSI command, analyzes the contents of the SCSI command, and starts DMA transfer between the data transfer control system and the storage device.
However, since various types of commands are transferred by using SBP-2, decode (analysis) processing of such commands increases the processing load and processing time.